Electric incandescent lamp.



J. H. DALE.

ELECTRIC INCANDESCENT LAMP.

APPLICATION FILED IAN. 20.19l5.

Patented M111. 5, 1919.

5] n ma wto'c UNITED STATES PATENT JOHN H. DALE, OF NEW YORK, N. Y.,ASSIGNOR TO DATE LIGHTING FIXTURE 00., 1110.,

' A CORPORATION OF NEW YORK- ELECTRIC TNCANDESCENT LAMP.

Specification of Letters Patent.

Application flled January 20,1915. Serial No. 3,198.

To all whom it may concern:

Be it known that I, JOHN H. DALE, a citizen of the United States,residing at the city of New York, in the borough of Man- .hattan andState of New York, have in- .vented certain new and useful Improvementsin Electric Incandescent Lamps, of which the following is a full, clear,and exact description.

This-invention relates to electric incandescent lamps, the object beingto provide a'construction therefor, which will prevent the conveyance ofan injurious amount of heat from the source of light of the lamp to thelamp base. descent lamp ordinarily comprises a metallic shell secured tothe glass wall of the lamp by cement or otherwise, the shell inclosingthe ends of the leading-1n wlres of the lamp which are soldered to thecontact parts associated with, or forming a part of,- the base. The basealso sometimes contains insulating material applied to the -conductorsand cementitious materials, which are subject to injury by excessivetemperatures. In the ordinary or original form of incandescnt lamp,wherein the filament burns in a vacuum, excessive heat 1s not conveyedto the base of the lamp because of the cementing materials in the baseand even to melt the solder of the joints thereof. This heating effectin the nitrogen lamp seems to be due to the presence of nitrogen itself,which becoming heated rapidly circulates within the bulb and raises thetemperature of the glass walls more rapidly than it can radiate to theexternal atmoshere. My invention is especially applicable to thenitrogen type of lamp, although not necessarily confined to this lamp,since it may perform a useful function whenever the base of a lamp mustbe kept at a comparatively low temperature. I accomplish the object ofthe invention by introducing a The base of an incanportion or skirt 10,

heat insulator between the wall of the lamp and the metallic base, whichinsulator comprises a vacuum chamber, and in carrying out the invention,I preferably use the wall of the neck of the lamp, as one wall of thevacuum chamber, and provide a special wall or dlaphragm inside of theneck which separates it from the chamber in which the filament elementis positioned. The metallic base 1s secured by cement or otherwise tothis wall of the neck which forms a part of the vacuum chamber'and isthereby insulated from the heat developed inside of the lamp. vIn theaccompanying drawings:

Figure 1 is a vertical-central section of my improved lamp, and

F1g. 2 is a similar view of a lamp showing a" modlfied form of heatinsulating vacuum chamber.

The lamp proper comprises the bulb 1, havlng, ascustomary in nitrogenlamps, an elongated integral neck 2. Within the lamp there Is an axialcolumn or post 3, projecting toward the center of the bulb, throughwhich the two leadin wires 4 and 5 extend. These wlres pro ect rom thecolumn to the middle zone of the bulb, and support between them anincandescent filament 6 of suitable form which is additionally supportedby wire braces 7 also sp'ringin from the column 3, or an extensionthereo Within the neck of the lamp there is formed a glass wall or diaphragm 8 made integral with the lamp bulb and spaced apart from the neck2,.thus forming an annular chamber 9, which chamber is exhausted of allair and gas when the lamp is made. The lamp base 13 has secured theretothe dependin metallic cup-shaped aving a plurality of openings to ermlta movement of air through the skirt and cool its interior, is positionedover the end of the neck 2, the walls of which form a part of the vacuumchamber and secured thereto, as usual, b means of cement 11 or in anyother suita le way. The base contains an insulated center contact 12 anda threaded shell or side contact 13 to which the ends of the twoconductors 4\and 5 are respectively soldered. These v the "incandescentfilamentG which is communicated to the nitrogen within the lamp, whichin turn, we will assume, circulates within the interior chamber of thelamp, causes the inner wall or diaphragm 8 of the vacuum chamber 'tobecome hea This heat however, is not communicate directly to the base ofthe lamp, but is prevented from reaching the base by the vacuum chamber9. As the heat from the inner wall 8 of the vacuum chamber'willpass-comparatively slowto the outer wall or neck 2, and

as the heat conducted upward throughthe vgall 2 from the point 15 where.it joins the bulb1,.will be at a slow rate, it'is evident that theradiation into the atmosphere from the neck 2 will be suflicient toprevent any undue communication of heat to the lamp base with the resultthat the lamp can be operated without danger of destroying the.

base or causing short circuits and the evil v result-s arisingtherefrom.

In the form of'my invention shown in Fig. 2, the vacuum chamber isformed by providing an integral glass diaphragm 16 acrom the neck of thelamp near the point where it joins the bulb. Thus, the upper or outerpart of thenormal lamp neck is converted into a sealed chamber which maybe exhausted and thereby serve as a heat insulating chamber, as beforedescribed, the lamp base being secured direct to the wall of this I By.making the lamp neck substantially the same length as in the formercase, it will be seenthat the heat chamber as shown.

from the bulb will have to travel the same considerable distance alongthe wall 2 to reach the lamp base and that, the vacuum will perform itsfunction in the same way as, and even with greater efiiciency than,inthe tormer construction. I My nvention, however, is-not-confined, inits broad aspect, to either of the forms illustrated, since itis obviousthat other modificatlons can be devised to bring about the ln-sertlonbetween the Wall of the lamp proper and the base, of an insulatingvacuum chamber, which is the substance of my invention the scope ofwhich is defined in the annexed claim.-

Th drawing illustrates. a cooling device for, thebulb 1, comprisingtubes 16' passing having openmgs secured to said base and constituting acooling chamber and a'vacuum chamber located between the skirt and thefilament chamber.

In witness whereof I subscribe my signature in the presence of twowitnesses.

' JOHN H. DALE.

Witnesses:

WALDO M. OHAPIN,

JosEPH A. BUGKLEY.

